Electrode for luminescent tubes



' Sept. 21 I926.

' r 1,600,595 P. F. J. LEBRUN ELECTRODE FOR LUMINESCENT TUBES Filed Spt.s, 1925 Inventor Pazdj ZLJeZ/zzn Attorney Patented Sept. 21, 1926;

UNITED STATES,

PATENT OFFICE.

PAUL FRANCOIS JOSEPH LEIBBUN, OF PARIS, FRANCE, ASSIGNOB OI ONE-HALF'1'0 MAURICE JULES QUEDBUE, OF MONTREAL, CANADA.

ELECTRODE FbB LUMINEBCENT TUBES.

Application filed September 8, 1825. Serial No. 55,102.

The present invention pertains to a novel lamp for luminescent tubesemployed in themanufacture of luminescent-signs consisting of a suitablybent glass tube filled with a conducting gas and having an electrodeateach end.

The object of the invention is the provision of a device designed forapplication to the ends of a luminous tube and containing the electrode.I

The device comprises a; bulb wh1ch is completely sealed except where' 1tis connected to the luminescent tube. The electrode contained within thebulb consists of a pair of metallic plates which intersect with oneanother and are connected to conductors passing through the wall of thetube and adapted to receive current from a convenient source.

A particular feature of the invention is that the plates are bents1nuously, preferably being substantially S-shaped 1n cross section.This construction affords a lar er electrode area for a given size ofcham er thanwould be possible if the plates were merely flat. Theincreased surface of the electrode provides a more intimate contactbetween the current and the gas within the bulb and allows more ra iddissipation of the heat of resistance. he plates are insulated from thebulb by means of balls received in apertures formed in the plates.

The invention is fully disclosed in the following description and in theaccompanying drawings in which Figure 1 is a longitudinal section of theelectrode showing the interior parts in elevation;

Figure 2 is a cross section of the electrode on the line 2'-2 of Figure1; and

Figures 3 and 4 are perspective views of the conducting lates.

Reference .to t ese views will now be made by use of like characterswhich are employed I to designate corresponding parts throughout.

The electrode comprises a bulb 1 connected or adapted for connection atone end to a luminescent tube 2 of a displa sign.

Luminescent tube signs are alrea y well.

known in the art and are constructed by bending a glass tube into thescript or design to be displayed. The tube is filled with a gas such asargon, helium or neon and isprovided with a lamp or electrode at eachend. When current is applied to the lamps or electrodes, it' alsofiowsthrough the gas in the curved tube and produces a luminous colourwhich is determined by the nature of the gas contained within thetube.

According to this invention the electrode contained with the bulb .1comprises a palr of plates 3 each having a slot 4 extending from themidpoint of one edge perpendicularly to the centre of the late. Theplates are then fitted to ether by means of the slots so that the s otofeach plate lies in alinement with the slot in the other plate, wherebythe height of the assembly is equal to the height of each plate.

The. ends of each plate lying parallel to the alined slots are curved inopposite directions as indicated by the numerals 5 and 6 in Figure 2.-The intermediate portion of each plate is allowed to remain plates haveapertures 11 in their corners adapted to receive spacing balls 12consistlng of glass, quartz or other vitreous material. The balls arenow placed in the apertures and the'electrode is inserted within I thebulb 1. The balls bear against .the inner wall of the bulb and therebyhold the electrode spaced and insulated from the bulb. 7

The ends 13 of the conductors are now' passed around'the open' end ofthe bulb and secured to the outer wall thereof. A jet or torch isapplied to the free edge of the bulb in order to form an interior tube14 which at the same time is welded to the bushing 10. Finally, a plu 15is applied over this .end of the tube an secured to the ends 13 of theconductors 8. The plug is of such shape that it may be inserted in anappropriate socket to receive current therefrom.

The plates 3 may consist of any suitable metal and their thickness maybe determined according to particular requirements. The

material of which the plates are made is preferably extra pure sheetiron. The curvature of the plates provides a greater discharge ofsurface for a bulb of a given size than is ossible with merely flatplates. A better istribution of current within the bulb and consequentlya more intimate contact between the current and the conducting gas isthus obtained. A further advantage of the larger surface of the platesis that the heat of resistance is more rapidly dissipated whereby thelamp is less likely to become overheated.

It has been found in practice that an electrode constructed in thismanner has a life of 10,000 hours or more. At the end of this period theelectrode is recharged with gas.

While a specific embodiment of the invention has been illustrated anddescribed, it is to be understood that various alterations in thedetails of construction may be made without departing from the spirit ofthe illvention as indicated by the appended claims.

Having thus fully described the invention,

what I claim as new and desire to protect by Letters Patent is 1. Anelectrode for luminescent tubes comprising a bulb adapted forcommunication with a. luminescent tube, a pair of intersectingconducting plates contained in the bulb and spaced from the wallsthereof, said plates being sinuously bent, a current conductor connectedto said plates, said bulb being completely sealed except Where.it'communicates with the luminescent tube.

2. An electrode for luminescent tubes comprising a bulb adapted forcommunication with a luminescent tube, a pair of intersecting conductingplates contained in the bulb and spaced from the walls thereof, saidplates being substantially S-shaped in cross section, a currentconductor connected to said plates, said bulb being completely sealedexcept where it con'nnunicates with the luminescent tube.

In witness whereof I have hereunto set my hand.

PAUL FRANCOIS JOSEPH LEBRUN.

